Scanners are an instrument used for a commercial POS system, and comprise two main types: common scanners and commercial scanners. With the emergence of barcode technology, the use of labels, such as barcodes, in market circulation is a general trend. Under such a background, barcode scanners are widely used.
Common interface types of barcode scanners are SCSI (small computer standard interface), EPP (enhanced parallel port), USB (universal serial bus interface) and PS2 (keyboard interface), which can thus easily interconnect with a computer. In commercial applications, according to different working principles, barcode scanners are mainly classified into laser scanners and imaging scanners, and according to different usage methods, can further be classified into handheld barcode scanners, desktop scanners and embedded scanners, etc. In various scanners, scanners with great portability develop rapidly because of their characteristics, such as small size and convenient operation. In recent years, a variety of portable scanners with new concepts have appeared on the market, and the scanning effects thereof are outstanding, and the scanning speed is fast, thereby being welcomed by many users.
A slim-type image scanner is a portable scanner developed recently, which can be made very thin and is fashionable in appearance. Because of its excellent portability, the slim-type image scanner can be carried around by users. Such a scanner is not only suitable for scanning a label on paper, but also suitable for scanning a label on a screen of an electronic device, such as a laptop computer, a tablet computer, a notebook, a netbook or a smartphone. Particularly, with the rapid development of mobile communication technologies, using the slim-type image scanner to scan a barcode on a smart phone screen has become a technique commonly used by users, and is widely used in applications such as microblog and Wechat.
A traditional scanner has an imager and an illumination component, and when a barcode to be scanned is placed in front of the imager, the illumination component provides illumination needed by an imager barcode scanner, and the illuminated barcode can reflect the light emitted by the illumination component for the imager to perform receiving and decoding. Although such illumination enables the barcode to reflect light with sufficient intensity, when the barcode is on the screen of an electronic device (such as a cell phone), the case where brightness is too high will occur in the field of view of the imager because of specular reflection, i.e., a bright spot being produced in a barcode region, causing decoding failure.
During specular reflection, the light is reflected from a single incident direction to a single emitting direction, and the light intensity may be too strong, which is unfavorable for the imager when performing receiving and decoding. Diffusively reflected light is reflected at many angles, rather than only reflecting at a single angle like specular reflection. In general, the reflection of a barcode on paper is diffusive reflection, so that the imager can obtain an image signal with appropriate intensity for decoding. However, the reflection of the barcode on a screen of an electronic device, such as a cell phone, is specular reflection, and thus the imager will capture an unexpected specular reflection image, thereby being unable to correctly decode the image of the barcode.
Therefore, there is a need for a scanner that can effectively avoid such a situation of specular reflection.